Tip bitcoin with bitfortip for Android
Or let's say someone wants to get a specific smartphone and after his own online research, he has found it for $500. He then offers a reward of 0.000139 BTC ($0.05) if someone can find it even cheaper, say $480. Then the person who finds it, is rewarded with 0.000139 BTC and the inquirer saves $20.
Or if you are unable to find an information on the internet on your own. You can post an inquiry along with a bitcoin reward for people to find you a certain link, image, item e.t.c .